这里面包含了一百多个JAVA源文件

				There is no method for replacing an item. To replace an item, first remove the item and then insert the new one. 
				    // Create a read-only combobox; the combobox is read-only
				    // in that it does not allow the user to type in a new item.
				    // The combobox still allows programmatic changes to its items.
				    String[] items = {"item1", "item2"};
				    JComboBox cb = new JComboBox(items);
				    
				    // Add an item to the start of the list
				    cb.insertItemAt("item0", 0);
				    
				    // Add an item after the first item
				    cb.insertItemAt("item0.5", 1);
				    
				    // Add an item to the end of the list
				    cb.addItem("item3");
				    
				    // Remove first item
				    cb.removeItemAt(0);
				    
				    // Remove the last item
				    cb.removeItemAt(cb.getItemCount()-1);
				    
				    // Remove all items
				    cb.removeAllItems();